The present invention relates to a high frequency power transistor provided with an internal shunt inductor.
Such power transistors are generally known. They are commonly provided with a post-matching stage formed by the internal shunt inductor. Such transistors have since long been utilised satisfactorily, however, as a basic electric component are continuously sought to be optimized and improved in performance.
According to the invention, such may surprisingly be realised by a relatively simple and highly cost efficient measure, according to which the shunt capacitor is produced in two separated capacities, each internally bonded to the transistor internal active die through internal leads, one of which capacities being connected to the transistor lead by a further bond wire.
By this measure, which may readily be applied at the manufacture of such transistors the output impedance is strongly increased, e.g. from about 2xcexa9 to about 19xcexa9 for a 30 W device at 2 GHz, which means that by appropriate choice of the internal wires the output impedance may relatively easy be adapted to customer requirements, while technically less circuit losses will occur.
The invention particularly is advantageous in, and therefore also relates to a parallel arrangement of a plurality of transistors at a high ohmic level. In such a circuitry scaling problems occur only to a lower extend, resulting in improved efficiency, gain and output power of any up-scaled device.
Surprisingly, also a quality improvement of the transistor is achieved by the present invention, since the internal lead wire between the transistor active die and the transistor lead, and the internal bandpass wire between the blocking capacitor and the active die, in the new arrangement have a greater distance, leading to a lower chance of mutual coupling so that the functioning of the inshin is improved. A particular advantage of the present improvement is that it can be implemented at virtually no cost.